1. Field of the Invention
The present invention relates generally to repair of transparent photomask substrates. More particularly, the present invention relates to efficient repair of transparent photomask substrates.
2. Description of the Related Art
Photomasks are an essential element for use in pattern transfer when fabricating microelectronic products. Photomasks typically comprise a transparent photomask substrate having formed thereupon opaque regions which serve as positive tone regions when photoexposing positive photoresist materials and as negative tone regions when photoexposing negative photoresist materials.
The reduction or elimination of photomask defects, both photomask pattern defects and photomask substrate defects, is generally of considerable importance within microelectronic product fabrication insofar as photomask defects are often in turn directly replicated into microelectronic product defects when fabricating microelectronic products.
The present invention is thus directed towards the repair of photomask defects.
Various photomask repair methods have been disclosed in the photomask fabrication art.
Included but not limiting among the photomask repair methods are those disclosed in: (1) Nakamura et al., in U.S. Pat. No. 5,639,699 (a deposition and etchback method for repairing protrusion defects and void defects within transparent photomask substrates); (2) Grenon et al., in U.S. Pat. No. 6,165,649 (a masking method for repairing opaque pattern defects within photomasks); and (3) Bae et al., in U.S. Pat. No. 6,329,106 (a two step focused ion beam and laser bean method for repairing bridging defects within phase shift photomasks).
The teachings of each of the foregoing references are incorporated herein fully by reference.
Desirable in the microelectronic product fabrication art are additional methods for repairing photomasks.
It is towards the foregoing object that the present invention is directed.